I recently got my hands on an Adams Arms 5.56 Tactical Elite PDW 5.56x45mm NATO/.223 Rem. gas piston/op-rod (operating rod) AR (AR-15) SBR (Short Barreled Rifle) upper receiver for one of my Sabre Defence AR carbine/SBR lowers. I have been trying to figure out which upper I was going to buy for my PDW build. Prior to having my own SBRs my work had issued me a Colt M4A1 Carbine [select-fire, with true full-auto vs. the standard M4 Carbine’s 3-round burst] for use on duty. I will tell you, I loved that gun. I shot over 25,000 rounds through that gun without a single malfunction. I did have some difficulty shooting frangible ammo through it, but I won’t count “frange” because I have never heard a gun that functioned well with frange ammo. The bottom line is, when I shot duty ammo or Lake City M855 ball 5.56mm NATO ammo, the gun ran without any issues. I took that gun through four different carbine courses, all of them had high round counts, and I easily fired over 2000 rounds at each of these courses. During these courses, I would shoot close to 1000 rounds between cleanings. I would simply put oil on the bolt carrier every 200 – 300 rounds and I was back on the line. Over the course of the numerous training evolutions, I would watch other manufactures weapons fail. I saw LMTs [Lewis Machine & Tool] sheer bolt lugs and Bushmasters fail to run, but my Colt would just keep on running. While taking a Tact Rifle (Tactical Rifle) course at DARC (Direct Action Resource Center), I saw an HK416 completely lock up, and we couldn’t even clear the weapon. While at Tact Rifle Instructor course at CSAT (Combat Shooting And Tactics), Paul Howe had gotten a bunch of LWRC rifles in. I and my buddy tried to help Paul sight them in, and we couldn’t even zero them! The guns would not shoot straight at all. I don’t know what the problem was, but I didn’t trust those guns, and was instantly apprehensive about piston guns. So after these incidents, I was not about to jump on the piston gun bandwagon. My Direct Impingement (DI) Colt M4A1 ran like a champ, and I trusted my LIFE and the lives of my teammates to it without hesitation.

I’d once had a discussion with a friend of mine who was a member of the State Department’s Mobile Security Deployment (Formerly, Mobile Security Division) and he told me similar stories and experiences with his M4. He would keep meticulous records of his round counts, and he told me over the 5 years he was with MSD he had less than ten malfunctions in over 250,000 rounds. He would shoot at least 1000 rounds a week and every year he would just get a new upper for his rifle and keep shooting. That was over 50,000 rounds per upper. You can’t ask for more than that. He would clean it once a week and the gun ran fine, oil the bolt carrier group every few hundred rounds and that was it. So between his experience and mine, I was sold on my M4 and the direct gas impingement (DGI) system; keep the bolt carrier group (BCG) lubed, and the gun will run. I eventually left the team because of a transfer, and I was not happy when I had to turn in my M4A1. In fact, I loved it so much that I purchased my own Colt Model LE6920 with the small trigger pins and set it up just like my M4A1. I’ve put a few thousand rounds through it, and it runs great. I use the same protocol of cleaning about every thousand rounds and just put oil on the bolt carrier every 200-300 rounds.

At the end of last year, I went to DARC and took DARC’s Advanced Urban Warfare Course. If any of you can get to that class, I would strongly encourage you to go; 2200 rounds of Simuntions fired in 6 days, with the last evolution lasting over 30 hours. DARC offers a Military version and a Law Enforcement version of this course. Both are amazing. The facility is awesome and the shoot houses were designed by SATAN!! I was using a drop-in bolt carrier conversion kit on a 14.5″ barrel. I did fine, but noticed that it was a little difficult to get target acquisition with the longer barrel length in the CQB (Close Quarters Battle) environment, which has a lot of confined spaces. I mentioned this to my friend Rich Mason, and he loaned me a Adams Arms 10.5″ upper to try out. I liked it so much, Rich let me use it for the remainder of the course. I was now a lot faster on target, and moved faster and smoother through the house and Mogadishu village using a gun in the SBR configuration.

After the course, I decided wanted a SBR and conducted some research on them. I spoke to some of my friends in the SF [U.S. Army Special Forces] community, and they began to “school” me on the realities of using a gun with barrel lengths of 10.5” or shorter. The overwhelming answer I got was they either work or they don’t. So, you basically have to keep buying uppers until you find one that works, or you make them work by having a gunsmith alter the gas port size to make the gun function reliably. I did not want to be bothered with that mess. Several of my SF buddies told me about several different companies were making “Piston Uppers” that were showing some promise in the SBR configurations. They also told me that the Adams Arms piston-driven system was the front runner for them all. I was told that some members were using these guns OCONUS and they were performing well in that environment. The other alternative was to buy a 12” gun. Every manufacturer I spoke with said that the 12” gun was the limit of how short you can cut down a barrel and still have a consistently reliable DI gun. I wanted a shorter gun because I wanted something I could use in a CQB environment with or without a suppressor. So I wanted to make sure the barrel would not be too long. Piston guns came up as “the way to go” for SBR configurations under 12” and that barrels lengths of 7” were possible while still being completely reliable. This was a problem for me because I was kind of a non-believer, due to the fact that I’d seen the HK416 sieze up, and I was hearing horror stories about how bad the HK 416 was doing. I was also told that the HK416 was only built to last 10,000 rounds. My Colt M4A1 ran way past that and cost a lot less.

Eventually, I found that several reputable companies made 7”, 7.5” and 10.5” uppers the problem was these uppers were expensive and I was having difficulty trying to figure out which upper to go with. I certainly did not want to go upwards of a $1000 for an upper and not be happy. So, I am shooting with my friend Ernest Langdon and he got his hands on an Adams Arms 5.56 Tactical Elite PDW 7.5″ AR SBR. I had been able to shoot some other piston uppers and I was impressed with the performance of these guns. I had shot one other 7” PDW SBR, and put 800 rounds through it in one day without one malfunction. I didn’t even put one drop of oil on the bolt carrier, I just shot it dry. The gun ran great, and with a couple more outings, I’m sure it would have performed well enough for me to trust my life to it. I spoke to a guy at the range that had 7500 rounds through his PDW “Piston Gun” without a malfunction and he never cleaned it. He told me that he wanted to see how long it would fire without cleaning it before it broke down or started malfunctioning. I was starting to gain some confidence in these piston systems.

Ernie let me shoot the Adams Arms 5.56 PDW Tactical Elite 7.5″, and by the end of the session, I wanted one. I researched Adams Arms and quickly learned that the company has a solid reputation and was advertising muzzle velocities that frankly were hard to believe. Ernie put me in touch with Jim Granger from Adams Arms. He patiently answered all of my questions, and by the end of the call, he offered to send me a PDW for a 90-day evaluation. Jim told me that if I didn’t like it or it didn’t perform, I could send it back without owing him a cent. I would only be out about the $25 it would cost to ship it back. That was too good an offer to pass up!

I had an upcoming training course scheduled with Matt Graham of Graham Combat, so I figured that would be a great time to test this upper out. I used it in Matt’s class, and fired over 700 rounds in two days. I only put three drops of oil on the bolt carrier every morning before we started shooting. During the course, there was a good amount of moving and shooting and the gun performed great. It was easy to handle, and I was able to make great hits with this upper. I easily made 60-yard shots, and was holding great groups with M855 and my Aimpoint Micro T-1 combat optic (optical gunsight). Head shots were no problem at that 60 yards. There were several different evolutions where we would be shooting out from the inside of the vehicle. Using the Adams Arms PDW was literally like cheating. I was in and out of the vehicle and acquiring targets extremely fast. Mounting the weapon and firing through the windshield while sitting behind the wheel was easy and really fast. If I’d tried to do that with a 12” or longer weapon, it would have been challenging at best. I could have easily fired at targets within 180 degrees with the Adams Arms 7.5-inch PDW with no issues.

Since then, I’ve taken the gun to the range on three other occasions, and it’s run flawlessly. As of this writing, I’m currently at 1500 rounds without a malfunction. In that time period, I’ve cleaned the gun once. Additionally, I shot a variety of ammo through the gun to see how reliable it was with ammo other than Lake City M855. Let’s face it, if your gun doesn’t work with Lake City M855 in it, it’s broken. I fired Winchester white box, XM193, MK 262 Mod 1, Winchester Ranger ammo and even a about hundred rounds of junk ammo that was mixed into ammo can. It was live ammo that has been recovered from the range over a few months that I got when we policed brass up on the range. This upper fired them all without a hiccup. At that point I was satisfied the upper was reliable. So for me it was a matter of ballistic performance and muzzle velocity.

As I stated earlier, Adams Arms advertised muzzle velocities that were hard to believe. So Ernie and I broke out the chronograph and decided to run some tests. We decided to do 5 round strings of fire with several different rounds to see how the guns measured up. Now this is in no way scientific but I can tell you that the muzzle velocities out of the Adams Arms PDW were consistently 130 – 190 feet per second faster than other guns in its class (other 7” guns). Below are the results of the 5 round strings of fire using a CED Millennium Chronograph with IR Sky Screens.

Lake City M855A1 (Not a typo or BS. I got my hands on about 10 rounds through a friend.)

1. 2357 Feet per second

2. 2380 Feet per second

3. 2378 Feet per second

4. 2377 Feet per second

5. 2382 Feet per second

The Adams Arms PDW was pushing velocities that were similar to 10.5” uppers. I shared the results with Jim Granger and he told me it was a combination of tolerances and parts being used as a system. Apparently the coating processes in conjunction with specific tolerances give them increased muzzle velocities

In the end I am sold on Adams Arms and their piston system. It has proven reliable and has awesome ballistics. The uppers are pretty inexpensive for the quality upper you are getting. All of my contacts that own them swear by them. Some have used them in combat with no issues and bet their lives on them. Jim and his staff have been great, have always answered any questions I have had, and clearly stand behind their products. The other companies that make piston guns in the PDW class are $300-$800 more expensive.

Now, I know that people will say the DI system works, and they are right. I will tell you my Colt 6920 works great and isn’t going anywhere, but I don’t think you can say that the DI system works well in the SBR configuration below 12” barrel lengths. In my opinion, if you want SBRs in the PDW barrel lengths, then you need to go with a piston upper. I have tested several different piston systems, and they all work exceptionally well. But when you look at quality, price, and the ballistic/muzzle velocities being put out by the Adams Arms uppers, then I think you’ll agree they are the way to go. I can tell you that all of my SBR’s will have an Adams Arms upper on them. I called Jim and told him that he is not getting the PDW back, and I ordered an 11” upper to which I’m going to mount an AAC M4-2000 muzzle can (silencer/sound suppressor).

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

One comment

a buddy of mine has an lwrc m6a2 that shoots sub moa with a wide spectrum of 62grn loads i personally own a sig 516 patrol that shoots moa with almost anything i feed it well anything brass at least i think they should label tula as like the standard bird load of ammunition eh i just think because you loved your colt so much your opinion about your experience with lwrc products was bias good article though makes me want to build an sbr with an an adams arms upper